freshlybakedca.ke
Git fork
1/*
2 * Low level 3-way in-core file merge.
3 *
4 * Copyright (c) 2007 Junio C Hamano
5 */
6
7#define USE_THE_REPOSITORY_VARIABLE
8#define DISABLE_SIGN_COMPARE_WARNINGS
9
10#include "git-compat-util.h"
11#include "config.h"
12#include "convert.h"
13#include "attr.h"
14#include "xdiff-interface.h"
15#include "run-command.h"
16#include "merge-ll.h"
17#include "quote.h"
18#include "strbuf.h"
19#include "gettext.h"
20
21struct ll_merge_driver;
22
23typedef enum ll_merge_result (*ll_merge_fn)(const struct ll_merge_driver *,
24 mmbuffer_t *result,
25 const char *path,
26 mmfile_t *orig, const char *orig_name,
27 mmfile_t *src1, const char *name1,
28 mmfile_t *src2, const char *name2,
29 const struct ll_merge_options *opts,
30 int marker_size);
31
32struct ll_merge_driver {
33 const char *name;
34 const char *description;
35 ll_merge_fn fn;
36 char *recursive;
37 struct ll_merge_driver *next;
38 char *cmdline;
39};
40
41static struct attr_check *merge_attributes;
42static struct attr_check *load_merge_attributes(void)
43{
44 if (!merge_attributes)
45 merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
46 return merge_attributes;
47}
48
49void reset_merge_attributes(void)
50{
51 attr_check_free(merge_attributes);
52 merge_attributes = NULL;
53}
54
55/*
56 * Built-in low-levels
57 */
58static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv UNUSED,
59 mmbuffer_t *result,
60 const char *path UNUSED,
61 mmfile_t *orig, const char *orig_name UNUSED,
62 mmfile_t *src1, const char *name1 UNUSED,
63 mmfile_t *src2, const char *name2 UNUSED,
64 const struct ll_merge_options *opts,
65 int marker_size UNUSED)
66{
67 enum ll_merge_result ret;
68 mmfile_t *stolen;
69 assert(opts);
70
71 /*
72 * The tentative merge result is the common ancestor for an
73 * internal merge. For the final merge, it is "ours" by
74 * default but -Xours/-Xtheirs can tweak the choice.
75 */
76 if (opts->virtual_ancestor) {
77 stolen = orig;
78 ret = LL_MERGE_OK;
79 } else {
80 switch (opts->variant) {
81 default:
82 ret = LL_MERGE_BINARY_CONFLICT;
83 stolen = src1;
84 break;
85 case XDL_MERGE_FAVOR_OURS:
86 ret = LL_MERGE_OK;
87 stolen = src1;
88 break;
89 case XDL_MERGE_FAVOR_THEIRS:
90 ret = LL_MERGE_OK;
91 stolen = src2;
92 break;
93 }
94 }
95
96 result->ptr = stolen->ptr;
97 result->size = stolen->size;
98 stolen->ptr = NULL;
99
100 return ret;
101}
102
103static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unused,
104 mmbuffer_t *result,
105 const char *path,
106 mmfile_t *orig, const char *orig_name,
107 mmfile_t *src1, const char *name1,
108 mmfile_t *src2, const char *name2,
109 const struct ll_merge_options *opts,
110 int marker_size)
111{
112 enum ll_merge_result ret;
113 xmparam_t xmp;
114 int status;
115 assert(opts);
116
117 if (orig->size > MAX_XDIFF_SIZE ||
118 src1->size > MAX_XDIFF_SIZE ||
119 src2->size > MAX_XDIFF_SIZE ||
120 buffer_is_binary(orig->ptr, orig->size) ||
121 buffer_is_binary(src1->ptr, src1->size) ||
122 buffer_is_binary(src2->ptr, src2->size)) {
123 return ll_binary_merge(drv_unused, result,
124 path,
125 orig, orig_name,
126 src1, name1,
127 src2, name2,
128 opts, marker_size);
129 }
130
131 memset(&xmp, 0, sizeof(xmp));
132 xmp.level = XDL_MERGE_ZEALOUS;
133 xmp.favor = opts->variant;
134 xmp.xpp.flags = opts->xdl_opts;
135 if (opts->conflict_style >= 0)
136 xmp.style = opts->conflict_style;
137 else if (git_xmerge_style >= 0)
138 xmp.style = git_xmerge_style;
139 if (marker_size > 0)
140 xmp.marker_size = marker_size;
141 xmp.ancestor = orig_name;
142 xmp.file1 = name1;
143 xmp.file2 = name2;
144 status = xdl_merge(orig, src1, src2, &xmp, result);
145 ret = (status > 0) ? LL_MERGE_CONFLICT : status;
146 return ret;
147}
148
149static enum ll_merge_result ll_union_merge(const struct ll_merge_driver *drv_unused,
150 mmbuffer_t *result,
151 const char *path,
152 mmfile_t *orig, const char *orig_name,
153 mmfile_t *src1, const char *name1,
154 mmfile_t *src2, const char *name2,
155 const struct ll_merge_options *opts,
156 int marker_size)
157{
158 /* Use union favor */
159 struct ll_merge_options o;
160 assert(opts);
161 o = *opts;
162 o.variant = XDL_MERGE_FAVOR_UNION;
163 return ll_xdl_merge(drv_unused, result, path,
164 orig, orig_name, src1, name1, src2, name2,
165 &o, marker_size);
166}
167
168#define LL_BINARY_MERGE 0
169#define LL_TEXT_MERGE 1
170#define LL_UNION_MERGE 2
171static struct ll_merge_driver ll_merge_drv[] = {
172 { "binary", "built-in binary merge", ll_binary_merge },
173 { "text", "built-in 3-way text merge", ll_xdl_merge },
174 { "union", "built-in union merge", ll_union_merge },
175};
176
177static void create_temp(mmfile_t *src, char *path, size_t len)
178{
179 int fd;
180
181 xsnprintf(path, len, ".merge_file_XXXXXX");
182 fd = xmkstemp(path);
183 if (write_in_full(fd, src->ptr, src->size) < 0)
184 die_errno("unable to write temp-file");
185 close(fd);
186}
187
188/*
189 * User defined low-level merge driver support.
190 */
191static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
192 mmbuffer_t *result,
193 const char *path,
194 mmfile_t *orig, const char *orig_name,
195 mmfile_t *src1, const char *name1,
196 mmfile_t *src2, const char *name2,
197 const struct ll_merge_options *opts,
198 int marker_size)
199{
200 char temp[3][50];
201 struct strbuf cmd = STRBUF_INIT;
202 const char *format = fn->cmdline;
203 struct child_process child = CHILD_PROCESS_INIT;
204 int status, fd, i;
205 struct stat st;
206 enum ll_merge_result ret;
207 assert(opts);
208
209 if (!fn->cmdline)
210 die("custom merge driver %s lacks command line.", fn->name);
211
212 result->ptr = NULL;
213 result->size = 0;
214 create_temp(orig, temp[0], sizeof(temp[0]));
215 create_temp(src1, temp[1], sizeof(temp[1]));
216 create_temp(src2, temp[2], sizeof(temp[2]));
217
218 while (strbuf_expand_step(&cmd, &format)) {
219 if (skip_prefix(format, "%", &format))
220 strbuf_addch(&cmd, '%');
221 else if (skip_prefix(format, "O", &format))
222 strbuf_addstr(&cmd, temp[0]);
223 else if (skip_prefix(format, "A", &format))
224 strbuf_addstr(&cmd, temp[1]);
225 else if (skip_prefix(format, "B", &format))
226 strbuf_addstr(&cmd, temp[2]);
227 else if (skip_prefix(format, "L", &format))
228 strbuf_addf(&cmd, "%d", marker_size);
229 else if (skip_prefix(format, "P", &format))
230 sq_quote_buf(&cmd, path);
231 else if (skip_prefix(format, "S", &format))
232 sq_quote_buf(&cmd, orig_name ? orig_name : "");
233 else if (skip_prefix(format, "X", &format))
234 sq_quote_buf(&cmd, name1 ? name1 : "");
235 else if (skip_prefix(format, "Y", &format))
236 sq_quote_buf(&cmd, name2 ? name2 : "");
237 else
238 strbuf_addch(&cmd, '%');
239 }
240
241 child.use_shell = 1;
242 strvec_push(&child.args, cmd.buf);
243 status = run_command(&child);
244 fd = open(temp[1], O_RDONLY);
245 if (fd < 0)
246 goto bad;
247 if (fstat(fd, &st))
248 goto close_bad;
249 result->size = st.st_size;
250 result->ptr = xmallocz(result->size);
251 if (read_in_full(fd, result->ptr, result->size) != result->size) {
252 FREE_AND_NULL(result->ptr);
253 result->size = 0;
254 }
255 close_bad:
256 close(fd);
257 bad:
258 for (i = 0; i < 3; i++)
259 unlink_or_warn(temp[i]);
260 strbuf_release(&cmd);
261 if (!status)
262 ret = LL_MERGE_OK;
263 else if (status <= 128)
264 ret = LL_MERGE_CONFLICT;
265 else
266 /* died due to a signal: WTERMSIG(status) + 128 */
267 ret = LL_MERGE_ERROR;
268 return ret;
269}
270
271/*
272 * merge.default and merge.driver configuration items
273 */
274static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
275static char *default_ll_merge;
276
277static int read_merge_config(const char *var, const char *value,
278 const struct config_context *ctx UNUSED,
279 void *cb UNUSED)
280{
281 struct ll_merge_driver *fn;
282 const char *key, *name;
283 size_t namelen;
284
285 if (!strcmp(var, "merge.default"))
286 return git_config_string(&default_ll_merge, var, value);
287
288 /*
289 * We are not interested in anything but "merge.<name>.variable";
290 * especially, we do not want to look at variables such as
291 * "merge.summary", "merge.tool", and "merge.verbosity".
292 */
293 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
294 return 0;
295
296 /*
297 * Find existing one as we might be processing merge.<name>.var2
298 * after seeing merge.<name>.var1.
299 */
300 for (fn = ll_user_merge; fn; fn = fn->next)
301 if (!xstrncmpz(fn->name, name, namelen))
302 break;
303 if (!fn) {
304 CALLOC_ARRAY(fn, 1);
305 fn->name = xmemdupz(name, namelen);
306 fn->fn = ll_ext_merge;
307 *ll_user_merge_tail = fn;
308 ll_user_merge_tail = &(fn->next);
309 }
310
311 if (!strcmp("name", key)) {
312 /*
313 * The description is leaking, but that's okay as we want to
314 * keep around the merge drivers anyway.
315 */
316 return git_config_string((char **) &fn->description, var, value);
317 }
318
319 if (!strcmp("driver", key)) {
320 if (!value)
321 return config_error_nonbool(var);
322 /*
323 * merge.<name>.driver specifies the command line:
324 *
325 * command-line
326 *
327 * The command-line will be interpolated with the following
328 * tokens and is given to the shell:
329 *
330 * %O - temporary file name for the merge base.
331 * %A - temporary file name for our version.
332 * %B - temporary file name for the other branches' version.
333 * %L - conflict marker length
334 * %P - the original path (safely quoted for the shell)
335 * %S - the revision for the merge base
336 * %X - the revision for our version
337 * %Y - the revision for their version
338 *
339 * If the file is not named identically in all versions, then each
340 * revision is joined with the corresponding path, separated by a colon.
341 * The external merge driver should write the results in the
342 * file named by %A, and signal that it has done with zero exit
343 * status.
344 */
345 fn->cmdline = xstrdup(value);
346 return 0;
347 }
348
349 if (!strcmp("recursive", key))
350 return git_config_string(&fn->recursive, var, value);
351
352 return 0;
353}
354
355static void initialize_ll_merge(void)
356{
357 if (ll_user_merge_tail)
358 return;
359 ll_user_merge_tail = &ll_user_merge;
360 repo_config(the_repository, read_merge_config, NULL);
361}
362
363static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
364{
365 struct ll_merge_driver *fn;
366 const char *name;
367 int i;
368
369 initialize_ll_merge();
370
371 if (ATTR_TRUE(merge_attr))
372 return &ll_merge_drv[LL_TEXT_MERGE];
373 else if (ATTR_FALSE(merge_attr))
374 return &ll_merge_drv[LL_BINARY_MERGE];
375 else if (ATTR_UNSET(merge_attr)) {
376 if (!default_ll_merge)
377 return &ll_merge_drv[LL_TEXT_MERGE];
378 else
379 name = default_ll_merge;
380 }
381 else
382 name = merge_attr;
383
384 for (fn = ll_user_merge; fn; fn = fn->next)
385 if (!strcmp(fn->name, name))
386 return fn;
387
388 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
389 if (!strcmp(ll_merge_drv[i].name, name))
390 return &ll_merge_drv[i];
391
392 /* default to the 3-way */
393 return &ll_merge_drv[LL_TEXT_MERGE];
394}
395
396static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
397{
398 struct strbuf strbuf = STRBUF_INIT;
399 if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
400 free(mm->ptr);
401 mm->size = strbuf.len;
402 mm->ptr = strbuf_detach(&strbuf, NULL);
403 }
404}
405
406enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
407 const char *path,
408 mmfile_t *ancestor, const char *ancestor_label,
409 mmfile_t *ours, const char *our_label,
410 mmfile_t *theirs, const char *their_label,
411 struct index_state *istate,
412 const struct ll_merge_options *opts)
413{
414 struct attr_check *check = load_merge_attributes();
415 static const struct ll_merge_options default_opts = LL_MERGE_OPTIONS_INIT;
416 const char *ll_driver_name = NULL;
417 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
418 const struct ll_merge_driver *driver;
419
420 if (!opts)
421 opts = &default_opts;
422
423 if (opts->renormalize) {
424 normalize_file(ancestor, path, istate);
425 normalize_file(ours, path, istate);
426 normalize_file(theirs, path, istate);
427 }
428
429 git_check_attr(istate, path, check);
430 ll_driver_name = check->items[0].value;
431 if (check->items[1].value) {
432 if (strtol_i(check->items[1].value, 10, &marker_size)) {
433 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
434 warning(_("invalid marker-size '%s', expecting an integer"), check->items[1].value);
435 }
436 if (marker_size <= 0)
437 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
438 }
439 driver = find_ll_merge_driver(ll_driver_name);
440
441 if (opts->virtual_ancestor) {
442 if (driver->recursive)
443 driver = find_ll_merge_driver(driver->recursive);
444 }
445 if (opts->extra_marker_size) {
446 marker_size += opts->extra_marker_size;
447 }
448 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
449 ours, our_label, theirs, their_label,
450 opts, marker_size);
451}
452
453int ll_merge_marker_size(struct index_state *istate, const char *path)
454{
455 static struct attr_check *check;
456 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
457
458 if (!check)
459 check = attr_check_initl("conflict-marker-size", NULL);
460 git_check_attr(istate, path, check);
461 if (check->items[0].value) {
462 if (strtol_i(check->items[0].value, 10, &marker_size)) {
463 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
464 warning(_("invalid marker-size '%s', expecting an integer"), check->items[0].value);
465 }
466 if (marker_size <= 0)
467 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
468 }
469 return marker_size;
470}